Electronic harpsichord loudspeaker arrangement and the like



J. MARKOWITZ 3,064,515 ELECTRONIC HARPSICHORD LOUDSPEAKER ARRANGEMENT AND THE LIKE Nov. 20, 1962 3 Sheets-Sheet 1 Filed Aug. 22. 1961 TIE--E- El E INVENTOB: Jmme Mrkowfi},

ZZORN Nov. 20, 1962 J. MARKOWITZ 3,064,515

ELECTRONIC HARPSICHORD LOUDSPEAKER ARRANGEMENT AND THE LIKE Filed Aug 22, 1961 3 Sheets-Sheet 2 TIE- LJeFrome marfiowiig,

BY a I in INVENTOR:

Nov. 20, 1962 J. MARKOWITZ 3,064,515

ELECTRONIC HARPSICHORD LOUDSPEAKER ARRANGEMENT AND THE LIKE Filed Aug. 22, 1961 5 SheetsSheet 3 INVENTOR:

rferome MarZ towil'g 3 064 51s ELECTRONIC HARPsrciroRD LOUDSPEAKER ARRANGEMENT AND THE LIKE Markowitz, Allentown, Pa., assignor to Allen This invention relates to electronic musical instruments, and more particularly concerns a unique electronic harpsichord and the like having a special loudspeaker system.

Ihe electronic harpsichord of my invention is a modern electrical musical counterinstrument to the 16th to 18th century mechanical wire-stringed keyboard instrument, which latter produced tones by the plucking of its strings with quill or leather points. In the design and production of my electronic harpsichord, those acoustic principles and techniques have been followed which will provide, as closely as possible, equivalency of the tonal qualities and characteristics of said mechanical harpsichord instruments. Since a harpsichord, in its more important usage, constitutes a personalized musical instrument, in that it is perhaps more frequently played for the enjoyment of only the player of the instrument, the trueness of the sound effects as directly heard by the player of such an instrument are of particular importance.

One object of my invention is to provide a novel electronic musical instrument, such as an electronic harpsichord and the like, which solves the indicated problem.

Another object is to provide such an instrument which has certain structural and functional features of advantage over the similar instruments of the prior art.

An additional object is to provide such an instrument which has a loudspeaker system that includes mediumfrequency loudspeakers and high-frequency loudspeakers positionally arranged on the instrument in a certain determined order in relation to the hearing area or ear location of the player of the instrument.

A further object is to provide such an instrument in which the medium-frequency loudspeakers indirectly transmit the sound emanating therefrom to the hearing area or car location of the instrument player by causing it to rebound from a sound-reflecting surface, such as the floor on which the instrument is supported, and the highfrequency loudspeakers directly transmit the sound emanating therefrom to the hearing area or ear location of the instrument player.

It is also an object to provide such an instrument in which a plurality of medium-frequency loudspeakers and one or more high-frequency loudspeakers are arranged on the instrument body in a certain determinedly spaced relationship with the hearing area or ear location of the instrument player for best hearing results at said location, for example, so that the sound waves emanating from the medium loudspeakers travel to the ears of the instrument player a distance in the order of about 83 inches and the sound waves emanating from the highfrequency loundspeakers travel to the ear location of the instrument player a distance in the order of about 30 inches.

With these and other objects in view, which will become more readily apparent from the following detailed description of the practical and illustrative embodiments of my improvements shown in the accompanying drawings, my invention comprises the novel electronic musical instrument, loudspeaker system, elements, features of construction and arrangement of parts in cooperative relationship, as more particularly indicated and defined by the hereto appended claims.

3,tl64,5l5 Patented Nov. 20, 1962 In the accompanying drawings:

FIGURE 1 is a top plan view of one form of electronic harpsichord in accordance with my invention.

FIG. 2 is a front elevational view of the harpsichord shown in FIG. 1.

FIG. 3 is a bottom plan view of the harpsichord shown in FIG. 1.

FIG. 4 is a side elevational view to a reduced scale of the harpsichord shown in FIG. 1 with certain portions of the harpsichord body broken away and indicating, more or less schematically, the path of travel of the sound waves from a certain loudspeaker arrangement to the ear location of the harpsichord player.

FIG. 5 is a top plan view to a reduced scale of the harpsichord as shown in FIG. 1 and indicating, more or less schematically, the path of travel of the sound waves from another loudspeaker arrangement to the ear location of the harpsichord player.

FIG. 6 is a schematic and block diagram of an electronic harpsichord in accordance with my invention.

Referring to the drawings, in which similar reference characters indicate corresponding parts, one form of an electronic harpsichord in accordance with my invention is there shown and generally comprises a console or body member 1, that is shaped as shown, is mounted on supporting legs 2 and has a keyboard 3 provided with the usual individual playing keys 4 of such an instrument.

The harpsichord of my invention is provided with a special loudspeaker system that includes two sets of loudspeakers, one of which sets consists of six mediumfrequency type speakers S S S S S and S and the other set consists of two high-frequency type speakers S and S As more particularly indicated in FIGS. 3, 4 and 5, the six medium-frequency loudspeakers 8 -8 are mounted in aligned, uniformly spaced relation within the bottom portion of the console or body member 1, and are arranged in such manner that the sounds or sound waves emanating therefrom will all travel in a substantially perpendicular, or vertical direction towards the floor surface F on which the harpsichord is supported. The purpose and function of these medium-frequency loudspeakers S to S will be hereinafter more particularly explained.

As indicated in FIGS. 1, 2 and 5, the two high-frequenvy speakers S7 and S are mounted in the console or body member 1, above and adjacent to the keyboard 2, in such manner that the sounds or sound waves emanating therefrom will travel directly, or unobstructedly, to the ear location of the instrument player. The purpose and function of these high-frequency loudspeakers will als be hereinafter more particularly described.

The electrical and electronic equipment of the harpsichord is mounted within the console or body member 1. The extent of this equipment and the circuitry thereof will become apparent from the simplified wiring diagram of FIG. 6.

The upper portion of the wiring diagram of FIG. 6 discloses the circuitry of the electrical and electronic equipment involved in producing a respective harpsichord tone when one of the playing keys 4 is depressed. Cooperatively associated with the key 4 is a pulse forming circuit consisting of capacitors 5 and 6 and resistors 7 and 8, that are connected with each other by conductors as clearly shown. The said pulse-forming circuit is ground ed, as indicated, and connected by two wires 9 with a conventional tone-producing oscillator 10. A conductor 11 connects the oscillator 10 with an amplifier 12 and the latter is connected by a wire 13 with the loudspeaker system generally indicated by the numeral 14.

The key 4 is movable between a pair of relatively 17. The said power supply may be in the form of a suitable direct current power, such as a battery, or a converter for converting commercial AC. power to DC. power, such power supply being of sufiicient capacity to provide the power required to operate the various elemerits of the entire circuitry.

The key 4 is normally in its open position, i.e., in its upper position as shown in FIG. 6, so that the key 4 will engage the contact P When the key 4 is depressed, so that-the key will engage contact point P a current pulse will be formed, the shape of which is principally determined by the size of the series capacitor 5, but is also affected by resistor 8 and capacitor 6. Upon releasing the key 4, so that it will move to its normally open position where it engages the contact P there will result a discharge of capacitor 5 through the resistor 7. The condenser 5 will then be in an essentially discharged state, when the key 4 is again depressed.

The lower sound or tone-producing circuit shown in FIG. 6 is like the upper such circuit which has just been described. Therefore, to avoid redundance of descriptive matter, the same reference numerals are applied to the corresponding parts of the lower circuit with the exponent a added thereto for purposes of differentiation.

The said upper and lower sound or tone-producing circuits are to be understood. as representative of a complete series, or set, of such circuits arranged for individual operation by each separate key of the keyboard.

The respective circuits of the said series of circuits differ from each other only in the size or value of the components making up the oscillators and associated pulse circuits. The shape of the pulse determines the important musical characteristics of the instrument which result in the distinctive harpsichord tone. Each oscillator 10 and 10 etc., is of the type uitlized in well-known circuits such as Hartley or Colpitts. The amplifier 12 may be of any usual or Well-known type the specifications of which are suitable for raising the power lever to the proper level required for the loudspeaker transducers and also to provide a suitable impedance matching between the oscillator and loudspeaker system 14.

The loudspeaker system 14 of the harpsichord consists of the six medium-frequency range type speakers 8 -8 that are arranged in the instrument console or body member 1 so that the sound waves will be initially directed in substantial parallelism with a vertical plane, and the two high-frequency type speakers S and S that are arranged in the console or body member 1, between the instrument player and the medium range speakers, in such manner that the sound waves emanating therefrom are initially directed in substantial parallelism with a horizontal plane, or an angular plane inclined in the direction of the ear location of the instrument player. I have found in practice that this speaker arrangement is important to the generation of a true harpsichord sound, particularly as heard at the location of the harpsichord player.

Analysis of the sound produced by the plucking of a taut wire string, as in the classic harpsichord, will reveal a relatively high-intensity burst of sound which is of a noise character with predominantly high-frequency content and said burst of sound occurs at the beginning of the pulse. The remainder of the pulse will consist of a damped oscillation consisting primarily of the fundamental frequency of the oscillator plus integral harmonics.

It is considered musically important that the initial burst 1 of sound be transmitted to the instrument player without undue attenuation in respect to the balance of the sound. Since high-frequency sounds are more directional than the middle and lower audio frequencies, the high-frequency speakers S1 and S are located nearest to the instrument player so that the attenuation of these highfrequency components of sound of the harpsichord will be at a minimum.

In order that the instrument player may control the relative high-frequency sound from the high-frequency speakers S7 and S to the sound heard from the speakers S to S there are provided three manually operable switches 18, 19 and 20.

FIGS. 4 and 5 illustrate, more or less schematically, the principal sound paths between the instrument player and the sound sources as they exist, or develop, when the electronic harpsichord of my invention is played. As previously indicated, the six medium-frequency loudspeaker S to S are mounted on the harpsichord console or body 1, so as to direct the sounds emanating therefrom towards the floor. The two high-frequency speakers S and S are respectively located at each side of the forward portion of the console and arranged so as to direct the sounds emanating therefrom in a substantially horizontal or in an angular plane towards the ear location of the instrument player.

In order that only the higher frequency components of the harpsichord sound be channeled into the high-frequency speakers, a conventional filter suitable for this purpose is connected between the high-frequency speakers and the amplifier, as indicated by the capacitors 21, 22 and 23 in FIG. 6.

Some of the essential features of the loudspeaker system are as follows: a

(l) The determined length differential of the sound paths of the medium-frequency and the high-frequency speakers. By reference to FIGS. 4 and 5, which indicate one actually measured exemplification, it will be noted that the total length of some of the paths of travel of the sound waves from the medium-frequency speakers S to S to the ear location of the harpsichord player may be in the order of about 83 inches (48 inches plus 35 inches). The length of the paths of travel of some of thesound waves from the high-frequency speakers S7 and S to the ear location of the harpsichord player may be in the order of about 30 inches. Therefore, in ac cordance with this actually measured exemplification the difference in length between the paths of travel of the sound waves emanating from the medium frequency and high-frequency speakers is consequently in the order of about 83 inches minus 30 inches, or 53 inches. This difference of about 53 inches will produce a sound transit time difference of approximately 3.9 milliseconds, resulting in a certain stereophonic type effect.

(2) The high-frequency speakers 8-; and S produce a relatively narrow beam of sound which, by virtue of the speaker location and arrangement, is directed to the ear location of the harpsichord player in such manner that the ears of the said player receive the direct sound radiation from said speakers. Accordingly, the high-frequency speakers S7 and S radiate only the high-frequencycomponents of the harpsichord sound pulses.

(3) The narrow sound beam, consisting of the highfrequency components that are directly transmitted (not reflected) to the ears of the harpsichord player, in combination with the lower, or medium-frequency sound components that reach the ears of the player approximately 3.9 milliseconds later, establish a sound transducer system having performance features that 'are'highly desirablefor the production of a true, or high fidelity'harpsichord tone.

Of course, it will be understood by those skilled in this art, that the improvements specifically shown and described, can be changed and modified in various ways without departing from the invention which is herein disclosed and the scope of which is more particularly indicated and defined by the hereto appended claims.

I claim:

1. An electronic musical instrument having the usual tone producing means and including at least two loudspeakers operatively associated therewith, at least one of said loudspeakers being of the medium-frequency type and at least one of said loudspeakers being of the highfrequency type, said medium-frequency loudspeaker being directed outwardly towards a surface of the room in which the instrument is located and said high-frequency speaker being directed outwardly directly towards a listener, whereby high-frequency tones are heard directly by the listener and medium-frequency tones are heard indirectly by the listener.

2. An electronic musical instrument in accordance with claim 1, that includes a playing console in which the loudspeakers are mounted.

3. An electronic musical instrument in accordance with claim 1, which includes a playing console having a keyboard arrangement and wherein at least one mediumfrequency loudspeaker is mounted in said console so as to face the floor of the room in which the instrument is located, and which includes two high-frequency loud- References (Iited in the file of this patent UNITED STATES PATENTS 2,513,109 Roth June 27, 1950 2,814,354 Brettell Nov. 26, 1957 2,879,683 Martin Mar. 31, 1959 2,888,517 Lindridge May 26, 1959 OTHER REFERENCES Tremaine, Audio Cyclopedia, 1st, ed., 1959. 

